1. Field of the Invention
This invention relates to a method for controlling an electromechanical load by at least one pulse switch converter and a device for implementing the method.
2. Discussion of the Related Art
The electronic control of electromechanical loads, and of motors in particular, is generally obtained by regulating current or voltage by means of chopping circuits. Signals such as binary signals are sent to pulse switches that provide dc currents or voltages for the electromagnetic loads according to the level of the chopping signal sent.
These chopper circuits induce high-frequency current ripples in the loads at multiples or sub-multiples of the working frequencies of the electronic switches. Thus the electromagnetic loads behave like loud-speakers, in such a way that these ripples cause acoustic noise at the corresponding frequencies.
Some solutions have already been proposed to avoid the drawback created by this acoustic noise. It is already known, in particular, how to make the switches operate using switching signals at inaudible frequencies (above 16 kHz) in the case of mono-switch systems, or, in the case of multi-switch systems, at frequencies such that the frequency of the resulting current ripple is inaudible.
These different solutions all propose switching at relatively high frequencies, and therefore impose the use of fast switches working at high switching speeds and for which supplemental filtering is also required to avoid generation of electromagnetic interference.